They got you in a headlock on the ground. Their head is in too close to do the frame escape. So, we know that we'll have to do the Leg Hook Escape. Well, hold on, they are throwing punches!

So first thing to do is to stay safe from punches. Once you block the punch, you have to pin their arm. After you pin their arm, grab onto their shoulder, hook your leg over, and make your way over onto the Modified Mount. Sure, you're still in the headlock, but you're in the top position. And you already know what to do from here - either set up to take the back, or break the grip and do an armbar.